On characterizing graphs with branchwidth at most four

Author

Riggins, Kymberly Dawn

Date

2001

Advisor

Dean, Nathaniel

Degree

Master of Science

Abstract

There are several ways in which we can characterize classes of graphs. One such way of classifying graphs is by their branchwidth. In working to characterize the class of graphs with branchwidth at most four beta 4 we have found a set of reductions that reduces members of beta 4 to the zero graph. We have also computed several planar members of the obstruction set Ob4 for graphs with branchwidth at most four. This thesis will summarize previous results on branchwidth and reveal the previously mentioned new results.